I've made two visits to the Marriott Marquis and loved everything but the miserable elevators. A mis begotten system if there ever was one.
The food, drinks and service at "The View", NYC's only revolving restaurant are superb.
The health club was very nice and the rooms are huge by New York standards.
There are two Starbucks on site with the ground floor store being the better source for pastries.
As an alternative there's a Dean & Deluca's accross the way on 46th street next to the Paramount Hotel. The Paramount is an interesting little boutique hotel and it is worth nosing into their lobby to see their eclectic collection of chairs. I've stayed in the Paramount let me say that the lobby and bar are about as far as you want to venture. The Marriott it ain't!